This invention relates to bowling balls and, more particularly, to novel and improved means incorporated into the structure of a bowling ball for regulating the dynamic balance of the ball while maximizing the physical properties inherent in the ball.
Bowling balls are conventionally composed of a machineable, thermosetting plastic having a smooth, spherical, outer surface. The ball may comprise a single, homogeneous plastic material, or may include a spherical core of one material surrounded by a shell of uniform thickness and of another material. In any case, it is a common practice to incorporate a weight member, also normally of a suitable material having a density significantly higher than that of the surrounding material, within the ball. The weight member is normally placed so that the center of gravity of the ball is at a location other than the geometric center of the ball. The location of the center of gravity is also changed when finger and thumb grip holes, and sometimes a balance hole, are drilled into the ball.
The action of the bowling ball as it travels down a lane is dependent upon the direction and velocity imparted by bowler's release, as well as the position of the weight block, and the amount of weight and location of the center of gravity. When a bowling ball is released in the usual manner, it tends to first rotate while sliding along the alley in its initial travel, and then change, at some point, depending on the factors mentioned above, from a sliding to non-sliding rotation. That is, in its initial travel, the axis of rotation of the ball is not parallel to the surface of the lane. The portion of the ball which contacts the lane surface during the sliding portion of the rotation is known as the bowler's "track". The track is a circle on the ball's surface other than a great circle and its position relative to the grip holes is dependent upon the factors set forth above. After a bowler has used a particular ball for a time, the position of the track is visually discernable.
The path of the ball is not the same during the slide and roll portions of the ball's travel. The change of direction experienced by the ball is known as the "break" or "snap". The point in the ball's travel where the break begins, as well as the relative abruptness, also depend largely on the factors noted above. Of course, the coefficient of friction between the ball and the lane also has a significant effect; thus, it is not uncommon for a bowler to have more than one ball, each having characteristics suited to the bowler's preference for the particular lane.
A primary object of a bowler is to achieve maximum striking power and pin action. To achieve this, it is necessary for a bowler to use a consistent delivery or release, and that the ball have balance characteristics, a center of gravity located to provide an optimum break point for a particular release, and inherent characteristics which produce a maximum amount of angular momentum for a given release.
The American Bowling Congress has set forth rules which must be abided by in competitive bowling. Included in these rules are the standards which define the "balance characteristics" previously mentioned. The rules state when the ball is weighed with the finger holes facing upwardly and the thumb hole positioned adjacent the weigher, the imbalance to the left and right, and fore and aft must not exceed one ounce, and the imbalance between the top and bottom must not exceed three ounces.
Once a bowler has acquired sufficient experience and technique to develop a reasonably consistent release, the balance characteristics and center of gravity location of the ball must be established to optimize ball action, and thus score, for that particular release on a lane of known characteristics. The bowler's release, basically a combination of velocity, lift and spin imparted by the bowler, as well as the position of the weight block, will result in a specific "track", i.e., the circular area on the ball surface which contacts the lane during ball travel. The track concentrically surrounds the axis of rotation which, in virtually all cases, is disposed at an oblique angle with respect to the horizontal lane surface. The further the weight block is removed from the track, the longer the ball will slide and the sharper it will break. Conversely, the closer the weight block is to the track, the earlier in its travel the ball will begin to roll and the more gradual the break.
The grip holes are drilled in the ball at a position relative to the weight block and the bowler's normal track to provide the general characteristics of slide, roll, and break desired for the particular bowler's delivery or release. In order to optimize balance characteristics, it may be necessary to drill an additional hole, removing sufficient material from the ball to produce the desired amount of relative imbalances between the three sets of ball hemispheres. U.S. Pat. No. 5,042,163 of the present inventor discloses methods and means of determining where on the ball's surface to drill and how much material to remove therefrom to provide optimum ball action for the particular bowler using the ball.
The present invention is concerned with incorporating into a bowling ball a weighted member having a shape which will optimize the ball's angular momentum for a given release, thus increasing the amount of pin action a bowler produces without changing his/her release. Furthermore, if the present invention is used in conjunction with applicant's aforementioned patent, the bowling ball will also be dynamically balanced (or imbalanced) in the manner best suited to the bowler's release and/or lane characteristics.
In the past, weighted members have been placed within a bowling ball for the sole purpose of compensating for weight removed from the ball in drilling finger and thumb holes. U.S. Pat. No. 4,320,899 issued to Salvino on Mar. 23, 1982 discloses a bowling ball construction in which a pair of rectilinear weight blocks are placed in the ball for the purpose of making all axes of the ball equal, thus eliminating wobble as it travels down the lane.
U.S. Pat. No. 4,913,429 issued to Fabanich on Apr. 3, 1990 discloses a bowling ball having a solid core which is substantially spherical in configuration. This core further includes a top weight of generally conical shape, and two extending side wings which are generally alike in configuration but placed at different angles with respect to each other. This weighted member's main disadvantage lies in the general nature of its shape; aside from being difficult to cast, too much weight is devoted to it's spherical center, thus producing a ball which is not much more useful than a bowling ball made without a weighted member.
U.S. Pat. Nos. 3,591,177 to Skuse and 3,865,369 to Randolph show further ball weights whose intended purpose is to offset the loss of material from the boring of grip holes.
It is a primary object of this invention to provide a bowling ball having a weighted member positioned therein which will optimize the ball's angular momentum for any given delivery, thus creating more pin action and raising a bowler's score.
It is another object of this invention to provide a bowling ball which will give a bowler the balance characteristics desired. Other objects will in part be obvious and in part appear hereinafter.